Ultrasound assessment of cervical nerve root enlargement in polyneuropathy is not confounded by neuroforaminal stenoses

•Common age-related cervical neuroforaminal stenoses on MRI/CT are not per se associated with nerve root enlargement on ultrasound.•Degeneration of the cervical spine is unlikely to confound the ultrasound assessment of cervical nerve roots in polyneuropathy.•Older age is associated with neuroforaminal stenosis, but is not a significant covariate of nerve root diameter in this cohort.